System and method for suppressing dns requests

ABSTRACT

A virtual private router (VPR) intercepts DNS requests and returns a pseudo IP address to the requesting application and the pseudo IP address is mapped to a domain name in the request. Requests for content including the pseudo IP address are modified to include the corresponding domain name and transmitted to an intermediary server, which resolves the domain name to a real IP address and forwards the content request. The content is received by the intermediary server, which returns it to the requesting application, such as by way of the VPR. Real IP addresses may be returned by the intermediary server such that subsequent content requests to the domain name may bypass the intermediary server. Requests for certain domains, ports, and/or protocols may bypass the intermediary server such that the VPR resolves the domain names to real IP addresses.

BACKGROUND

Most of the content available on the Internet is associated withUniversal Resource Locators (URL), which reference content servers bytheir domain names. To request the content from a specific contentserver, its domain name must be translated to a numerical IP address.This translation is performed by the Domain Name Service (DNS). Beforeissuing content request, the client computer asks a DNS server to maprequested domain name to an IP address. The client may cache the DNSresponse for an allowed interval (time to leave: TTL), but must issuenew DNS request if caching time expires, or if requested domain is notstored in the DNS cache.

Each DNS request increases the time required to fetch the content: theclient must wait to receive the DNS response before issuing a contentrequest. A slow DNS server may decrease the perceived speed of Interneteven when content servers are fast. If a DNS response contains a CNAMErecord (alias of one domain name to another), the client may need toissue another DNS request, further delaying content retrieval. DNSlatency is especially high for mobile networks and can reach 200 to 300ms for 3G networks.

One known way to suppress client-side DNS requests is to send HTTP orHTTPS traffic from the client computer through a proxy server, whilesupplying domain name with each content request. If the client-sideapplication is aware that it's connected trough the proxy server (forinstance, Internet Explorer browser, distributed by MicrosoftCorporation, provides support for proxy settings), it doesn't issue DNSrequests. Instead, the proxy server issues its own DNS requests forspecified domains.

Shifting DNS resolution to a proxy server usually decreases overalllatency (especially when client is connected to the mobile network) aswell as client-side data traffic. If multiple users are connected to thesame proxy server with large DNS cache, it increases the probabilitythat requested DNS response is already cached, further increasingperformance. However, multiple client applications, especially on mobiledevices, do not support proxy settings and continue to issue DNSrequests even when being connected through a proxy server that discardsclient-side DNS results and issues its own DNS requests. Client-side DNSrequests are also discarded when client is connected through a VPNserver that terminates HTTP and/or HTTPS connections and uses its ownDNS resolver.

Therefore, there is a need to decrease number of DNS requests from theclient computer over the computer network, especially when clientcomputer is connected to a proxy or VPN server.

BRIEF DESCRIPTION OF THE FIGURES

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limiting of its scope, the invention will be describedand explained with additional specificity and detail through use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram of a network environment forperforming methods in accordance with an embodiment of the presentinvention;

FIG. 2 is a process flow diagram of a method for suppressing DNSrequests in accordance with an embodiment of the present invention;

FIG. 3 is a process flow diagram for bypassing DNS request suppressionfor some domain names in accordance with an embodiment of the presentinvention;

FIG. 4 is a process flow diagram of a method for processing contentrequests including non-routable IP addresses in accordance with anembodiment of the present invention

FIG. 5 is a process flow diagram of a method for processing contentrequests with non-routable IP addresses with application of intermediateserver bypass rules in accordance with an embodiment of the presentinvention; and

FIG. 6 is a process flow diagram of a method for processing TCP contentrequests in accordance with an embodiment of the present invention;

FIG. 7 is a process flow diagram of a method for processing contentrequests including non-routable IP addresses including bypassing of anintermediary server in accordance with an embodiment of the presentinvention;

FIGS. 8A through 8C are process flow diagrams of method for forwardingcontent requests by an intermediary server for various protocols inaccordance with an embodiment of the present invention;

FIG. 9 is a process flow diagram for processing VPN traffic inaccordance with an embodiment of the present invention;

FIG. 10 is a process flow diagram for reducing latency in VPN sessionsin accordance with an embodiment of the present invention;

FIG. 11 is a process flow diagram of a method for suppressing DNSrequests while populating a IP address table of a client device inaccordance with an embodiment of the present invention;

FIG. 12 is a process flow diagram of a method for providing IP addressesin anticipation of DNS requests in accordance with an embodiment of thepresent invention; and

FIG. 13 is a schematic block diagram of a computer system suitable forimplementing methods in accordance with embodiments of the presentinvention.

DETAILED DESCRIPTION

It will be readily understood that the components of the invention, asgenerally described and illustrated in the Figures herein, could bearranged and designed in a wide variety of different configurations.Thus, the following more detailed description of the embodiments of theinvention, as represented in the Figures, is not intended to limit thescope of the invention, as claimed, but is merely representative ofcertain examples of presently contemplated embodiments in accordancewith the invention. The presently described embodiments will be bestunderstood by reference to the drawings, wherein like parts aredesignated by like numerals throughout.

Software on a client computer, further referred to as a Virtual PrivateRouter (VPR), intercepts one or more DNS requests initiated by one ormore client applications, returns pseudo IP address for the requesteddomain name, and stores correspondence between requested domain name andreturned pseudo IP address. The pseudo IP address is not required tocorrectly map requested domain to a real content server.

After returning one or more pseudo IP addresses, VPR detects one or morecontent requests having a pseudo IP address as a destination, retrievesdomain name corresponding to detected pseudo IP address and then submitscontent request together with a descriptor of a retrieved domain name toan intermediary server. The intermediary server resolves a descriptor ofthe submitted domain name to an IP address corresponding to a realcontent server, which forwards content requests to that server andreturns content response to the client computer. As a result, clientapplication receives requested content without sending DNS requests overthe computer network, thereby decreasing latency and amount of datatraffic.

In one embodiment, the VPR determines whether the content request shouldbe sent through an intermediate server or should bypass an intermediaryserver. If the content request should bypass an intermediary server, theVPR issues a DNS request over the computer network and returns real IPaddress; if the content request should be sent through an intermediaryserver, VPR returns pseudo IP address without issuing a DNS request overthe computer network.

The determination whether to send the content request through anintermediary server can depend on a set of routing rules associated withone or more parameters from the group of domain name, port, andprotocol. In one implementation, the VPR determines whether requestshould bypass an intermediary server before returning a response to anintercepted DNS request; this determination is made by matchingrequested domain name to one or more routing rules.

In another implementation, the VPR always returns pseudo IP addressafter intercepting DNS request, and then, upon receiving a contentpacket having pseudo IP address as a destination, obtains one or moreparameters from the group of domain name associated with that IPaddress, port and protocol, matches obtained parameters with one or morerouting rules and, if content request should bypass an intermediaryserver, issues its own DNS request for a real IP address of the obtaineddomains name, and then issues direct content request using obtained realIP address.

In one embodiment, the pseudo IP address is a non-routable IP address.In one implementation, non-routable IP address is selected from thegroup of non-routable IPv4 addresses within at least one of the ranges10.0.0.0-10.255.255.255, 172.16.0.0-172.31.255.255 and192.168.0.0-192.168.255.255. In another implementation, the pseudo IPaddress is a non-routable IPv6 address. In one other implementation,non-routable IP addresses used as pseudo IP addresses are selected fromone or more ranges different from the ranges used by the local networkto which client computer is connected. In another implementation, thepseudo IP address is a network address associated with the transportprotocol other than IPv4 or IPv6.

In some embodiments, after client sends content request through the VPNtunnel, the VPN server issues its own DNS request for a requested domainname and replaces destination IP address with the one obtained from theDNS request. In one embodiment, this replacement is performed afterdis-encapsulating the traffic from the VPN tunnel. In anotherembodiment, it is performed while the traffic is still encapsulatedinside the VPN tunnel. HTTP and HTTPS proxy servers typically must issuetheir own DNS requests because their data packets don't contain realdestination IP address (it is replaced by the address of the proxyserver in some embodiments). Prior art VPN servers don't performadditional DNS requests for data packets already containing destinationIP: they just remove encapsulation headers and send original packets totheir destinations.

In one embodiment, retrieval of the domain corresponding to detected IPaddress comprises extracting subset of the pseudo IP address and usingthat subset to reference stored domain name, thereby allowing to keepthe same reference between IP address and domain name for differentranges of pseudo IP addresses. In one implementation, retrieved subsetof the pseudo IP address contains no more than 20 lowest bits of the32-bit integer representation of the IPv4 pseudo IP address.

In one embodiment, VPR returns pseudo IP address with a large TTL value,thereby decreasing number of DNS request that must be intercepted.

In one embodiment, intermediary server includes at least one proxyserver; VPR redirects content request from one or more client-sideapplications to a client side proxy, which forwards the request to thatproxy server over a computer network together with requested domain. Inone implementation, one or more HTTP content requests are submitted to aclient side HTTP proxy, which forwards requested domain inside HOSTheader. In another implementation, one or more HTTPS content requestsare submitted to a client side HTTPS proxy, which forwards requesteddomain inside SNI header. In one other implementation, one or more TCPcontent requests are submitted to client side connect-proxy, whichforwards requested domain inside CONNECT header.

In one embodiment, intermediary server resolves descriptor of therequested domain name to an IP address by issuing a DNS request. In oneimplementation, descriptor of the domain name comprises a text stringspecified in the DNS request intercepted by VPR. In anotherimplementation, descriptor of the domain name is a pointer to a textstring, while an intermediary server obtains the value of the textstring from a data storage pointed by the descriptor, before resolvingrequested domain name to an IP address.

In one embodiment, VPR submits two or more content request to at leasttwo different intermediary servers; intermediary server for each contentrequest is determined by obtaining one or more parameters of the contentrequest from the group of domain name associated with that IP address,port and protocol, and then matching these parameters with one or morerouting rules.

In another embodiment, intermediary server is a VPN server; VPRencapsulates one or more content requests inside the VPN tunnel betweenthe client computer and the VPN server. In one implementation, VPRsubmits descriptor of the requested domain name inside the VPN tunnel.In one implementation, descriptor of the requested domain name is addedto the set of data packets of a TCP or a UDP connection having pseudo IPas a destination IP address, before these data packets are encapsulatedinside the VPN packets.

In some embodiments, intermediary server sends real IP address (one itresolved by issuing its own DNS request) back to the client, togetherwith content data. Client later uses that address to issue requests inbypass of the intermediary server, without issuing its own DNS requests.The client thereby uses the intermediary server in this embodiment toavoid sending DNS requests, but only until it gets real IP in theresponse. As a result, client mitigates performance degradation due tothe additional hop through the intermediary server, while still usingpseudo IPs instead of its own DNS requests.

Embodiments in accordance with the invention may be embodied as anapparatus, method, or computer program product. Accordingly, theinvention may take the form of an entirely hardware embodiment, anentirely software embodiment (including firmware, resident software,micro-code, etc.), or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a “module” or“system.” Furthermore, the invention may take the form of a computerprogram product embodied in any tangible medium of expression havingcomputer-usable program code embodied in the medium.

Any combination of one or more computer-usable or computer-readablemedia may be utilized. For example, a computer-readable medium mayinclude one or more of a portable computer diskette, a hard disk, arandom access memory (RAM) device, a read-only memory (ROM) device, anerasable programmable read-only memory (EPROM or Flash memory) device, aportable compact disc read-only memory (CDROM), an optical storagedevice, and a magnetic storage device. In selected embodiments, acomputer-readable medium may comprise any non-transitory medium that cancontain, store, communicate, propagate, or transport the program for useby or in connection with the instruction execution system, apparatus, ordevice.

Computer program code for carrying out operations of the invention maybe written in any combination of one or more programming languages,including an object-oriented programming language such as Java,Smalltalk, C++, or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages, and may also use descriptive or markup languages such asHTML, XML, JSON, and the like. The program code may execute entirely ona computer system as a stand-alone software package, on a stand-alonehardware unit, partly on a remote computer spaced some distance from thecomputer, or entirely on a remote computer or server. In the latterscenario, the remote computer may be connected to the computer throughany type of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).Computer networks may use transport protocols other than InternetProtocol. Correspondingly, present invention could be implemented fortypes of network addresses other than IP addresses.

The invention is described below with reference to flowchartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products according to embodiments of the invention. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, can be implemented by computerprogram instructions or code. These computer program instructions may beprovided to a processor of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable data processing apparatus, createmeans for implementing the functions/acts specified in the flowchartand/or block diagram block or blocks.

These computer program instructions may also be stored in anon-transitory computer-readable medium that can direct a computer orother programmable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide processes for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.

FIG. 1 illustrates an example network architecture 100 in which themethods disclosed herein may be implemented. In particular, a computingdevice, such as a the computing device 1300 of FIG. 13 may store andexecute one or more applications 102. In particular, the applications102 may include such applications as a web browser or other applicationthat sends or receives data from a remote device over a network.

The computing device 1300 may likewise host a virtual private router(VPR) 104, the functionality of which is described in greater detailbelow. In particular, the VPR 104 may include a traffic interceptor 106that intercepts both of requests for domain name resolution (e.g. domainname service (DNS) requests) as well as requests for content ortransmission of content from the applications 102.

DNS resolution requests may be processed by a DNS resolver 108. Asdescribed in greater detail below DNS resolver 108 may receive a DNSresolution request from an application 102 and, in response, return anon-routable IP address (hereinafter “pseudo IP address”) to theapplication 102. In some embodiments and circumstances, the DNS resolver108 may respond to DNS requests from an application 102 by transmittingan actual DNS request to a DNS server, receiving a routable IP address(hereinafter also referred to as a “real IP address”) and return theroutable IP address to the application 102. The DNS resolver 108 mayrecord mappings between domain names and pseudo IP addresses generatedby the DNS resolve 108 in response to requests to resolve the domainnames. The DNS resolver 108 may also store mappings between domains andreal IP addresses resolved by the DNS resolver 108.

The VPR 104 may further include a content router 110. Requests forcontent received from an application 102 is processed by the contentrouter 110 by identifying a pseudo IP address in the content request,retrieving a domain name mapped to that pseudo IP address, and outputs amodified content request that includes the domain name. Responses tocontent requests may be received by the content router 110 and returnedto the application 102.

The modified content requests may be processed by an appropriate module112-116 corresponding to the content request. For example, HTTP contentrequests may be processed by an HTTP proxy 112, a CONNECT contentrequest may be processed by a CONNECT proxy 114. Communications within aVPN tunnel may be processed by a VPN module 116. Content requests andother communications may then be transmitted by the modules 112-116 toan intermediate server 118. In some embodiments, the VPR 104 mayimplement more or fewer then the illustrated modules 112-116. In someembodiments, the VPR may further implement a firewall for preventingunauthorized access.

In one embodiment, intermediary server 118 includes at least one proxyserver. The VPR 104 redirects DNS request including a requested domainfrom one or more client-side applications to a client side proxy (e.g.one of modules 112-116), which forwards the request to the intermediaryserver 118 operating as a proxy server over a computer network togetherwith requested domain. In one implementation, one or more HTTP contentrequests are submitted to a client side HTTP proxy 112, which forwardsrequested domain inside a HOST header. In another implementation, one ormore HTTPS content requests are submitted to a client side HTTPS proxy,which forwards requested domain inside an SNI (server nameidentification) header. In one other implementation, one or more TCPcontent requests are submitted to client side CONNECT proxy 114, whichforwards requested domain inside a CONNECT header.

In one implementation, VPR submits two or more content requests to atleast two different intermediary servers; intermediary server for eachcontent request is determined by obtaining one or more parameters of thecontent request from the group of domain name associated with that IPaddress, port and protocol, and then matching these parameters with oneor more routing rules. For instance, intermediary server for requesteddomain is selected to retrieve content specific to the location ofintermediary server (such as local news), or to improve performance (forinstance, to minimize deviation from the direct route between the clientand the content server).

The illustrated components of the VPR 104 may be stored and executed bya single client device 1300 or distributed across multiple computingdevices, such as on a gateway computer or a router connected to theclient device 1300 by a local or some other network.

The intermediate server 118 may receive the modified content requestsand other communications, extract the domain name, resolve the domainname to an IP address, and forward the modified content request to thatIP address. In some embodiments, an intermediary server 120 may receivedthe content requests and may be embodied as a VPN server that managesVPN connections while reducing DNS requests as described in greaterdetail below. The intermediary server 118 may also function as a VPNserver or forward content requests and other communications within a VPNtunnel to some other VPN server.

The intermediary servers 118, 120 may be coupled to the Internet 122 orsome other network such as a local area network (LAN), wide area network(WAN) or some other network. Connections to the Internet 122 may be bymeans of any wired or wireless connection. Servers that are the targetfor content requests and transmit responses thereto may be understood tobe included in the Internet 122 and may include any device that may beaddressed by network communications and transmit a response thereto. Thecomputing device 1300 (see FIG. 13) that stores and executes theapplications 102 and VPR 104 may likewise transmit and receive data fromthe internet such as requests for DNS name resolution and responsesthereto.

FIG. 2 illustrates a method 200 that may be executed by a VPR 104,specifically the DNS resolver 108. The method 200 may includeintercepting 202 a DNS request and getting 204 from the DNS the fullyqualified domain name (FQDN) from the DNS request. An attempt is made toget 206 a pseudo IP corresponding to the FQDN from a table mapping FQDNsto pseudo IPs (FQDN_to_nr_IP table). The FQDN_to_nr_IP table may be ahash table taking an FQDN as a key and the corresponding pseudo IPaddress as the value corresponding to that key. Other tables describedherein may likewise be embodied as hash tables.

If an entry determined 208 to not be found in the table, then a newpseudo IP address (nr_IP) is allocated 210. The allocated pseudo IPaddress may be unique within the scope of the VPR or some other namespace within the VPR such that the pseudo IP address will uniquelyresolve to the FQDN obtained at step 204. In one implementation, thepseudo IP address is allocated 210 from the group of non-routable IPv4addresses within at least one of the ranges 10.0.0.0-10.255.255.255,172.16.0.0-172.31.255.255 and 192.168.0.0-192.168.255.255. In anotherimplementation, the pseudo IP address is a non-routable IPv6 address. Inone other implementation, non-routable IP addresses used as pseudo IPaddresses are selected from one or more ranges different from the rangesused by the local network to which client computer is connected.

In one implementation, non-routable IP addresses used as pseudo IPaddresses are selected from one or more ranges different from the rangesused by the local network to which client computer is connected. In oneembodiment, retrieval of the domain corresponding to detected IP addresscomprises extracting a subset of the pseudo IP address and using thatsubset to reference stored domain name, thereby allowing one to keep thesame reference between IP address and domain name for different rangesof pseudo IP addresses. For example, pseudo IP addresses of length Mbits may be stored as only the least significant N bits, N<M. In oneimplementation, retrieved subset of the pseudo IP address contains nomore than 20 lowest bits of the 32-bit integer representation of theIPv4 pseudo IP address.

For instance, the VPR 104 receives a DNS request for a domain“example.com”, which doesn't have a valid entry in the FQDN_to_nr_IPtable. To avoid conflict with other resources on the local network, VPRshould return a pseudo IP address in an IP range different from therange used by the current local network. For example, if user iscurrently connected to a local network with IP addresses within a range192.168.0.0-192.168.255.255, VPR returns pseudo IP in a range10.0.0.0-10.255.255.255 (for instance, 10.17.18.19 having last 20 bitsequal to 0×11213), after making sure that no other FQDN is associatedwith the pseudo IP address having the same last 20 bits in theFQDN_to_nr_IP or in the nr_IP_to_FQDN table. The unique pair <FQDN→last20 bits of pseudo IP address”>is stored in both FQDN_to_nr_IP table(domain as a key) and in the nr_IP_to_FQDN table (last 20 bits of pseudoIP address as a key).

At some later time, the user may switch to a different local network,for instance with IP addresses in a range 10.0.0.0-10.255.255.255. Afterreceiving another DNS request for a domain “example.com”, VPR retrievesthe last 20 bits of the pseudo IP from nr_IP_to_FQDN table, and thenreturns pseudo IP for a different range (for instance,172.16.0.0-172.31.255.255), for example, pseudo IP 172.17.18.18, havinglast 20 bits 0×11213. In this manner, the tables do not need to bechanged in response to the user switching to a different range of localIP addresses. In one other example, different number of bits of pseudoIP address can be stored, while remaining smaller than the number ofbits describing the real IP address. For instance, FQDN_to_nr_IP andnr_IP_to_FQDN tables may store 16 least significant bits of IPv4address, or store portions of IPv6 address without at least some bits ofthe routing prefix, subnet identifier or an interface identifier.

In another example, both FQDN_to_nr_IP and nr_IP_to_FQDN store fullpseudo IP address (10.17.18.19), but the most significant bits or otherbits are ignored while generating pseudo IP address in another rangehaving the same low bits. As a result, the same reference between pseudoIP and domain name can be used in different local networks without therisk of conflicting with non-routable IP addresses assigned to localresources. This allows one to keep stored references longer, instead ofclearing portions of FQDN_to_nr_IP and nr_IP_to_FQDN tables afterdetecting the switch of the local network.

The method 200 further includes updating 212 the FQDN_to_nr_IP table tomap the FQDN obtained at step 204 to the allocated 210 pseudo IPaddress. Likewise, an entry is created in a nr_IP_to FQDN table thatmaps the allocated 210 pseudo IP addresses to the FQDN obtained at step204.

A time to leave (TTL) for the pseudo IP address is set 214 to themaximum allowable value for a given DNS protocol implemented by the VPR104 and/or the application, or to another value large enough to reducethe frequency of DNS requests for the same FQDN, for instance one largerthan the TTL value used for the real IP address. This will reduce thenumber of DNS requests by the application due to expiring of the TTL. ADNS response is created 316 that includes the pseudo IP addressallocated at step 210 and the TTL set at step 314 and the DNS responseis returned 218 to the application that generated the intercepted 202DNS request.

In some instances, the TTL of a pseudo IP address may expire such thatan application may issue another request to resolve a domain name againor another application may request to resolve a domain name for which aprevious resolution request has been intercepted 202. In either case,the FQDN identified at step 204 will be found 208 to have acorresponding entry in the FQDN_to_nr_IP table. In response, the method200 may include setting 214 to a maximum value the TTL for the pseudo IPaddress from the table corresponding to the FQDN at step, creating 216 aDNS response including the pseudo IP address mapped to the FQDN in thetable and the TTL set at step 214, and returning 218 the DNS response tothe application that generated the intercepted 202 DNS request. TTL mayalso be set to some other value that is large enough to reduce thefrequency of DNS requests for the same FQDN, for instance one largerthan the TTL value used for the real IP address.

The method of FIG. 2 advantageously suppresses DNS requests therebyreducing latency, particularly for mobile devices.

Referring to FIG. 3, in some embodiments the VPR 104, specifically theDNS resolver 108, may bypass some DNS requests from the processillustrated in FIG. 2. For example, the intermediary server 118, 120 maynot be geographically proximate the computing device 1300 hosting theVPR 104. Accordingly, some domains may provide access tolocation-specific content, such as local news, sports, weather,retailers, etc. It therefore may be advantageous to have the VPR 104resolve the DNS request rather than the remote intermediary server 118,120.

For example, the method 300 may include intercepting 202 a DNS requestand getting 204 a FQDN from the DNS request as described above withrespect to FIG. 2. The method 300 may further include attempting to get302 a routing rule corresponding to the FQDN, such as from aFQDN_to_rules table that maps FQDNs to routing rules. If a rule isdetermined 304 to not be found, the method 300 may include getting 306 adefault routing rule. If the rule from the table or the default rule isdetermined 308 to not require bypassing of the intermediary server 118,120, then the method 300 may include performing steps 206-218 asdescribed above with respect to FIG. 2 in which a pseudo IP address isreturned to the application that issued the intercepted 202 DNS request.

If the routing rule from the table or the default rule is found 308 torequire bypass, then the method 300 may include attempting to get 310 areal IP address corresponding to the FQDN from step 204, such as from aFQDN_to_r_IP table that maps FQDNs to corresponding real IP addresses.If an entry is found, then the TTL for the entry is set to the remainingTTL for that real IP address, e.g. the amount of the TTL received forthe real IP address from a DNS server that has not yet elapsed since thereal IP address was received. A DNS response including the real IPaddress and the TTL may be created 216 and returned 218 to therequesting application.

If a real IP address is not found corresponding to the FQDN of step 204,then the method 316 may include sending 316 a DNS request to a DNSserver including the FQDN of step 204; receiving 318 a responseincluding a real IP address for the FQDN of step 204 and a TTL; updatingthe FQDN_to_r_IP and r_IP_to_FQDN tables to map the FQDN to the real IPaddress and the real IP address to the FQDN, respectively; and returning218 the DNS response received at step 318 to the requesting application.The TTL for the real IP address may also be stored in association withthe entries in the FQDN_to_r_IP and r_IP_to_FQDN tables FQDN_to_r_IPtable may contain more that one IP address for the same FQDN; r_IP_toFQDN table may contain more than one FQDN for the same real IP. In suchcases, one of the multiple values associated with same key may beselected by using random selection, round-robin, or other algorithms.

In another implementation, VPR 104 always returns pseudo IP addressafter intercepting DNS request. For example, steps 206-218 may beperformed in every instance regardless of whether a routing rules aredetermined 308 to require bypassing of the intermediary server 118, 120.In such embodiments, if the routing rules are determined 308 to requirebypassing of the intermediary server, the steps 316-320 may be omittedsuch that a real IP address is not obtained until a content requestreferencing the FQDN is received.

Where a pseudo IP address is allocated 210 even where bypassing isdictated by the routing rules, the VPR, upon receiving a content packethaving a pseudo IP address as a destination, may obtain one or moreparameters from the packet, such as some or all of a domain nameassociated with that pseudo IP address, port and protocol. The VPR 104then matches the obtained parameters with one or more routing rules and,if content request should bypass an intermediary server per the routingrules, the VPR 104 issues its own DNS request for a real IP address ofthe obtained domains name and then issues direct content request usingobtained real IP address, i.e. transmits the content request to theserver addressed by the real IP address without first sending thecontent request to the intermediary server 118, 120.

FIG. 4 illustrates a method 400 that may be executed by a VPR 104, suchas by the content router 110. The method 400 may include determining 402whether the content request includes a pseudo IP address (i.e.non-routable IP address), such as in the destination IP field of thecontent request. If so, then the method 400 includes attempting to get404 the FQDN corresponding to that pseudo IP address from thenr_IP_to_FQDN table. If the pseudo IP address is found 406 in the table,the corresponding FQDN from the table is added 408 to the contentrequest and the content request is sent 410 to the intermediary server118, 120. If no entry is found 406 for the pseudo IP address, then anerror is returned 412.

If the content request is found 402 to not include a pseudo IP addressbut rather a real IP address, then an attempt is made to get 414 theFQDN corresponding to the real IP address in the r_IP_to FQDN table. Ifa FQDN corresponding to the real IP address is not found 416 in thetable, or if multiple FQDNs are found for the same real IP address, thenthe content request may simply be sent 410 to the intermediary server118, 120 with the real IP address. If a unique FQDN is found, then theFQDN is added 408 to the content request and the content request is thensent 410 to the intermediary server 118, 120.

The method 400 includes sending content requests to the intermediaryserver 118, 120 in every instance even when the content requests do notinclude a pseudo IP address. Upon receiving the content requests, realIP addresses may be obtained by the intermediary server 118, 120 forFQDNs included in the content requests, in some embodiments even forcontent requests that included real IP addresses.

In an alternative embodiment, rather than adding 408 the FQDN to thecontent request, the VPR 104 sends the content request with the pseudoIP address to the intermediary server 118, 120. The VPR 104 furthercorresponds with the intermediary server 118, 120 to communicate thecurrent version of the nr_IP_to_FQDN table to the intermediary server118, 120 prior to intercepting content requests and/or forwardingcontent requests to the intermediary server 118, 120. Updates to thenr_IP_to_FQDN may be sent periodically or as changes occur, such as eachtime a new pseudo IP address is allocated 210 or every X milliseconds.In response to receiving a content request, the intermediary server 118,120 may use its copy of the nr_IP_to_FQDN table to retrieve the FQDN andresolve it to a real IP address.

FIG. 5 illustrates a method 500 that may be executed by a VPR 104, suchas by the content router 110 and that includes bypassing theintermediary server 118, 120 under certain circumstances. As notedabove, bypassing of the intermediary server 118, 120 may advantageouslybe done for certain domains for various reasons, such as to ensure thatlocally relevant content is returned in response to the contentrequests.

The method 500 may include determining 502 whether the content requestincludes a pseudo IP address (i.e. non-routable IP address). If so, thenthe method 500 includes attempting to get 504 the FQDN corresponding tothat pseudo IP address from the nr_IP_to_FQDN table. If the pseudo IPaddress is found 506 in the table, then an attempt may be made to get512 a routing rule corresponding to the FQDN gotten at step 504 from atable, such as a FQDN_to_rules table that maps routing rules to FQDNs.

If the content request is found 502 to not include a pseudo IP addressbut rather a real IP address, then an attempt is made to get 508 theFQDN corresponding to the real IP address in the r_IP_to_FQDN table. Ifa FQDN corresponding to the real IP address is found 510 in the table,then an attempt may be made to get 512 a routing rule corresponding tothe FQDN gotten at step 508 from a table, such as the FQDN_to_rulestable. If r_IP_to_FQDN table contains multiple FQDNs for the same realIP, the rule can be selected from the set of rules for these FQDNs. Forinstance, send the content request through the intermediate server if atleast one of these FQDNs has association with this rule.

If a routing rule is found 514 for the FQDN obtained at step 504 or 508,then the method 500 may include determining 516 whether the routing rulerequires bypassing of the intermediary server 118, 120 by contentrequests. If so, then the content request is sent 518 to the destinationspecified in the content request. Specifically, if the content requestincludes a real IP address, then the content request is sent to thatreal IP address. If the content request included a pseudo IP address,then the FQDN corresponding to that pseudo IP address (such as the FQDNmapped to the FQDN in the FQDN_to_nr_IP table) may be resolved to a realIP address by issuing a DNS request, receiving a response including areal IP address, modifying the content request to include the real IPaddress, and sending the modified content request to the real IPaddress. An example method of sending content requests in bypass of theintermediary server 118, 120 is described below with respect to FIG. 7.

If the routing rule is determined 516 to not require bypassing of theintermediary server 118, 120, then the content request including theFQDN determined at one of steps 504 and 508 is sent 520 to theintermediary server 118, 120.

If a routing rule is not found 512 for the FQDN determined at one ofsteps 504 and 508, then an attempt may be made to get 522 a routing rulecorresponding to one or both of a port and a protocol (HTTP, TCP, VPN,CONNECT, etc.) corresponding to the content request, such as in aport_proto_to_rules table that maps each port and/or protocol to arouting rule corresponding to the each port and/or protocol. If arouting rule is determined 524 to be found, then the routing rule isapplied at step 516 as described above. If a rule is determined 524 tonot be found, then a default rule may be set 526 and this default ruleapplied at step 516 as described above.

In some embodiments, the routing rules associated with a particularFQDN, protocol, and/or port may be dynamically changed, such as based onadditional tests for requested FQDNs. For instance, content requests maybe sent through the intermediary servers 118, 120 for the content storedfar from the client but close to the intermediary server, or bypassedfor the content stored closer to the client than to intermediary serveras determined from testing response times for content requests.

In some embodiments, in addition to specifying whether content requestsshould bypass the intermediary servers 118, 120, the routing rules mayfurther specify, based on the attributes of the content request, otheraspects of the routing of the content request. For example, a routingrule may specify additional information, such as whether to send thecontent request through the proxy or VPN, or which intermediary server118, 120 to use. In one implementation, VPR 104 submits two or morecontent requests to at least two different intermediary servers. Theintermediary server 118, 120 for each content request is determined byobtaining one or more parameters of the content request from the groupof domain name associated with that IP address, port and protocol, andthen matching these parameters with one or more routing rules. Forinstance, the intermediary server 118, 120 for a requested domain isselected to retrieve content specific to the location of intermediaryserver (such as local news), or to improve performance (for instance, tominimize deviation from the direct route between the client and thecontent server).

In some embodiments, the DNS resolver 108 may use only rules specifyingwhether to bypass an intermediary server, whereas the content router 110may use additional information to route the content request throughrequested module 112-116 or some other module. In one example, a routingrule may specify sending TCP traffic for destination port 80 throughHTTP proxy 112, all other TCP traffic through CONNECT proxy 114 andtraffic using any other protocol is routed through VPN module 116. Inanother example, routing rules may dynamically change to increasesecurity in public WiFi hotspots where unencrypted data exchange can beintercepted by third parties. For instance, HTTP traffic (TCP port 80)can be sent through HTTP proxy to improve performance in secure WiFihotspot, or through secure VPN to protect user in public WiFi hotspot.The method by which the security of a WiFi hotspot is determined may beaccording to U.S. application Ser. No. 61/921,781 filed Dec. 30, 2013and entitled SYSTEM AND METHOD FOR SECURITY AND QUALITY ASSESSMENT OFWIRELESS ACCESS POINTS, which is hereby incorporated by reference in itsentirety for all purposes. The method by which the security of a WiFihotspot is determined may also be according to U.S. application Ser. No.14/574,240 filed Dec. 17, 2014 and entitled SYSTEM AND METHOD FORSECURITY AND QUALITY ASSESSMENT OF WIRELESS ACCESS POINTS, which ishereby incorporated by reference in its entirety for all purposes.

FIG. 6 illustrates a method 600 that may be executed by a VPR 104, suchas by the content router 110 with respect to content requestsintercepted by the traffic interceptor 106. The method 600 may beexecuted in combination with the methods of FIGS. 3-5. Specifically,content requests with their corresponding FQDNs, if included in thecontent requests or added thereto according to the methods of FIGS. 3-5,are determined to be routed to an intermediary server 118, 120 accordingto some or all of the methods 300-500 may be processed according to theprotocol in which the content requests were generated.

For example, the method 600 may be performed with respect to anintercepted content request. The method 600 may include determining 602whether the content request is a transmission control protocol (TCP)content request. If so, whether the content request is an HTTP(hypertext transmission protocol) request is evaluated at step 604. Ifso, then the content request is sent 606 through the HTTP proxy 112 tothe intermediary server 118.

If the content request is determined 604 not to be an HTTP request, thenwhether an FQDN was found in the content request or resolved to thecontent request according to a pseudo IP address as described above. Ifso, then the FQDN is added to the CONNECT header of the content requestand the content request as modified is sent 612 through the CONNECTproxy 114. If no FQDN is determined 608 to be found, then the method 600includes evaluating 614 whether the content request included a pseudo IPaddress. If not, then the content request included a real IP address andmay be sent 612 through CONNECT proxy 114. If the content request isfound 614 to include a pseudo IP address then an error is returned 616.In one embodiment, the FQDN is added to the CONNECT request only if thatFQDN is uniquely associated with an IP address. If more than one FQDN isassociated with the same real IP address, the request is sent throughthe CONNECT proxy without adding the FQDN in such embodiments.

If the content request is determined 602 to be other than a TCP contentrequest, then the method 600 may include evaluating 618 whether an FQDNwas found in the content request or resolved to the content requestaccording to a pseudo IP address as described above. If so, then theFQDN is added 620 to the content request and the content request is sent622 through the VPN module 116. If an FQDN is determined 618 not to befound in or for the content request, then at step 624 it is evaluatedwhether the content request includes a pseudo IP address. If so, then anerror is returned 616. If not, then the content request is sent 622through the VPN module 622.

FIG. 6 is one example of three possible protocols (HTTP, CONNECT, VPN)for which content requests may be received. In other embodiments, otherprotocols may be used and content requests routed through correspondingmodules for implementing transmission of such content requests.

FIG. 7 illustrates an example method 700 by which the VPR 104,specifically the content router 110, may process content requestsselected to bypass the intermediary server, such as according to themethod 500 of FIG. 5. The method 700 may include determining 702 whetherthe content request includes a pseudo IP address. If not, then thecontent request is simply sent 704 to the real IP address included inthe content request. If so, then the method 700 may include evaluating706 whether an FQDN is found corresponding to the pseudo IP address,such as in the nr_IP_to_FQDN table. If not, then an error is returned708. If so, then a real IP address is obtained for the FQDN by sending710 a DNS request with the FQDN, getting 712 a response to the DNSrequest with the real IP address, updating 714 the FQDN_to_r_IP andr_IP_to FQDN tables to include the mapping between the FQDN and the realIP address, and replacing 716 the pseudo IP address with the real IPaddress in the content request. The content request as modified may thenbe sent 704 to the real IP address. In addition to storing the mappingbetween domain names and IP addresses, content router may also storemappings between non-routable IP addresses and real IP addresses,updating this mapping upon receiving the real IP address after anon-routable IP address is already assigned to the same domain.

FIGS. 8A through 8D illustrate a method 800 that may be executed by theintermediary server 118, 120 for content requests for various protocols.The steps of FIG. 8A may be executed for HTTP content requests. For HTTPrequests, the method 800 may include determining 702 whether the contentrequest includes a pseudo IP address. If not, then the content requestis simply sent 804 to the real IP address included in the contentrequest. If so, then the method 800 may include getting 806 an FQDN fromthe host header of the HTTP content request. A real IP address isobtained for the FQDN by sending 808 a DNS request with the FQDN,getting 810 a response to the DNS request with the real IP address, andreplacing 812 the pseudo IP address with the real IP address in the HTTPcontent request. The HTTP content request as modified may then be sent804 to the real IP address.

As is apparent from FIG. 8A and as will be apparent with respect toFIGS. 8B through 8D, content requests modified to include a FQDN due totheir including a pseudo IP address as described in the other methodsherein may still include the pseudo IP address when transmitted to theintermediary server 118, 120, such as in a destination IP field, therebyfacilitating determining whether DNS resolution by the intermediaryserver 118, 120 is required.

Referring to FIG. 8B, for non-HTTP TCP content requests, the method 80may include determining 814 whether the content request includes apseudo IP address. If not, then the content request is simply sent 816to the real IP address included in the content request. If so, then themethod 800 may include attempting to get 818 a FQDN from the CONNECTheader and evaluating 820 whether an FQDN is found in the CONNECTheader. If not, then an error is returned 822. If so, then a real IPaddress is obtained for the FQDN by sending 824 a DNS request with theFQDN, getting 826 a response to the DNS request with the real IPaddress, and replacing 828 the pseudo IP address with the real IPaddress in the content request. The content request as modified may thenbe sent 816 to the real IP address.

Referring to FIG. 8C, for VPN content requests, the method 80 mayinclude determining 830 whether the content request includes a pseudo IPaddress. If not, then the content request is simply sent 832 to the realIP address included in the content request. If so, then the method 800may include attempting to get 834 a FQDN from the data included in thecontent request and evaluating 836 whether an FQDN is found in therequest data. If not, then an error is returned 838. If so, then a realIP address is obtained for the FQDN by sending 840 a DNS request withthe FQDN, getting 842 a response to the DNS request with the real IPaddress, and replacing 844 the pseudo IP address with the real IPaddress in the content request. The content request as modified may thenbe sent 832 to the real IP address.

FIGS. 8A through 8C describe methods wherein DNS resolution is performedby requesting DNS name resolution from a DNS server. However, the method800 may further include caching domain name resolutions, such as in aFQDN_to_r_IP table that maps each FQDN to a real IP address previouslyreceived for that FQDN. Accordingly, upon identifying a FQDN for acontent request, the real IP address may be retrieved form this table.

In some embodiments, content requests may be generated by the VPR thatdo not include actual domain names but rather pointers to stringsrepresenting the domain names. A table including the domain names may beshared between the VPR 104 and the intermediary server 118, 120 suchthat the intermediary server may resolve pointers to domain names byresolving each pointer to a text string in the table.

FIG. 9 illustrates a method 900 that may be executed by the VPR 104 andan intermediary server 120 functioning as a VPN server 120. The method900 may include intercepting 902 by the VPR 104 VPN traffic andevaluating 904 whether the traffic includes a pseudo IP address. If not,then the traffic may be transmitted 906 to the VPN server 120 withoutmodification of addressing of the traffic.

If so, then the method 900 may include retrieving 908 the FQDN for thepseudo IP address, such as from the FQDN_to_nr_IP table described above.The FQDN may then be added 910 to the traffic within the VPN tunnel andthe modified traffic may be transmitted 912 to the VPN server 120.Adding 910 of the FQDN may include inserting an additional packet to thetraffic or adding the FQDN to a field of some or all of the packets ofthe intercepted 902 traffic. In one embodiment, a descriptor of the FQDNis added to the set of data packets of a TCP or a UDP connection havingpseudo IP as a destination IP address, before these data packets areencapsulated inside the VPN packets.

Transmitting 912 the traffic may include first encapsulating the trafficas modified within a VPN tunnel. As known in the art, a VPN tunnel mayinclude encrypting the packets and including the encrypted packetswithin VPN packets with a corresponding VPN header that are then sent tothe VPN server 120. In some instances, the VPN traffic intercepted 902may already include the FQDN, such as in a HOST, SNI, or CONNECT header,in which case steps 908-910 may be omitted and the traffic may beencapsulated and transmitted 912 to the VPN server 120 without additionof the FQDN.

The VPN server 120 may receive 914 the modified traffic, which maydis-encapsulating VPN packets to obtain the modified traffic. As knownin the art, dis-encapsulating may include stripping of the VPN headerand decrypting the encapsulated traffic. The FQDN may be extracted 916by the VPN server 120 from the modified traffic and resolved 918 to areal IP address. Resolving 918 the FQDN to a real IP address may includeissuing a DNS request with the FQDN and receiving the real IP address inresponse. Resolving 918 may include retrieving the real IP address froma table mapping previously resolved FQDNs to real IP addresses.

In some embodiments, the VPR 104 may include a pointer to a text stringin the modified traffic rather than the FQDN, the text string includingthe FQDN. Accordingly, extracting 916 the FQDN may include retrievingthe text string corresponding to the pointer.

In some embodiments, the VPR 104 and VPN server 120 may share thenr_IP_to_FQDN table, i.e. the VPR 104 may periodically transmit thetable or updates to the table to the VPN server 120 such that the VPNserver 120 has a current copy of the table. Accordingly, the trafficneed not be modified by the VPR 104—the VPN server 120 will receive thetraffic and resolve the pseudo IP addresses to FQDN using its version ofthe nr_IP_to_FQDN table.

Once a real IP address is obtained, the VPN server 120 may replace 920the pseudo IP addresses in the received 914 traffic with the real IPaddress and transmit 922 the traffic as modified at step 920 to the realIP address, i.e. the computer system having the real IP address assignedthereto.

The method of FIG. 9 is different from the conventional approach to VPNservers. HTTP and HTTPS proxy servers must issue their own DNS requestsbecause their data packets do not contain real destination IP address(it is replaced by the address of the proxy server). However, prior artVPN servers do not perform additional DNS requests for data packetsalready containing a destination IP address—they just removeencapsulation headers and send original packets to their destinations.

Referring to FIG. 10, in some embodiments a VPN server 120 may reducelatency for client devices connecting thereto regardless of whether theclient devices execute a VPR 104 as described herein. For example, theVPN server 120 may perform the illustrated method 1000 with respect tocontent requests received within a VPN connection. The method 1000 mayinclude receiving 1002 a content request including a routable IP addressand identifying 1004 a corresponding domain name for the routable IPaddress, such as by issuing a reverse DNS (rDNS) request to a DNS serveror retrieving the routable IP address from a cache mapping routable IPaddresses to domain names according to responses to previous DNS or rDNSrequests.

The method 1000 may further include issuing 1006 a DNS request for thedomain name identified at step 1004 and receiving 1008 a routable IPaddress in return that may be different from that identified at step1004. Upon receiving 1008 the different routable IP address, the contentrequest may be modified to include the different routable IP address andtransmitted 1012 to the server system having the different routable IPaddress.

For instance, a client device in Europe issues DNS request for a domaincorresponding to content servers both in Europe and United States ofAmerica, and then receives real IP address for a content server inEurope. This IP address decreases access latency when the contentrequest is issued directly from the client while in Europe. However, ifthe client from Europe establishes connection to a VPN server 120 inUnited States of America, the provided real IP address may causesignificant performance degradation: client request will be sent fromVPN server 120 in the USA to the content server in Europe. The responsewill be sent to VPN server 120 in USA and then back to the client inEurope. By the VPN server 120 issuing 1006 a DNS request, the domainname may be resolved to the IP address of a closer server systemcorresponding to the same domain name thereby reducing latency.

In some embodiments, Accordingly to the present invention, VPN server120 detects that it needs to issue 1006 an additional DNS request andreplaces provided destination IP address by the one obtained from DNSresponse. In the example above, the VPN server 120 may evaluate the realIP address and detect that the provided real IP references contentserver in Europe. In response, the VPN server 120 issues 1006 its ownDNS request and receives 1008 a response referencing a closer contentserver, e.g. the USA in the above example, thereby improvingperformance. In one implementation, detection that additional DNSrequest is needed comprises (a) resolving a geo-location of therequested real IP address received at step 1002 and (b) causingadditional DNS request to be issued if the requested real IP address isdetermined to reference a content server located in a geographic regiondifferent from the one of the VPN server 120, e.g. the content server isoutside of a political or geographic region (country, state, continent)or is more than a threshold distance away from the VPN server 120. TheVPN server 120 may therefore be made to store, or be programmed toobtain, its own location to facilitate this comparison. In instanceswhere the geographic regions of the VPN server 120 and content serverare the same or are otherwise determined to be within the thresholddistance from one another, then the real IP address received at step1002 is not changed by the VPN server 120 and the content requests aretransmitted to the content sever corresponding to the real IP addressreceived at step 1002.

FIG. 11 illustrates a method 1100 that may be executed by the VPR 104and an intermediary server 118 in order to reduce DNS requests by bothof the VPR 104 and the intermediary server 118. The method 1100 mayinclude receiving 1102 a content request and evaluating 1104 whether thecontent request at least one of (a) includes a real IP address, (b)includes a pseudo IP address that is mapped to a FQDN for which the realIP address is stored by the VPR 104, or (c) includes a FQDN for whichthe VPR 104 has stored a corresponding IP address. For example, if thecontent request includes a pseudo IP address, the corresponding FQDN maybe looked up in the nr_IP_to_FQDN table. The real IP addresscorresponding to the FQDN included in the content request or determinedfrom the pseudo IP address may be retrieved from the FQDN_to_r_IP tableif an entry for that FQDN exists. Stated differently, step 1104 mayinclude determining whether a real IP address may be determined by theVPR 104 without issuing a DNS request using only cached data on thecomputer system 1300 by the VPR 104.

If the real IP address to which the content request is addressed can beresolved by the VPR as described above with respect to step 1104, thenthe content request is transmitted 1106 by the VPR 104 to the serversystem corresponding to that real IP address directly without firsttransmitting the content request to the intermediary server 118.

If the content request is found 1104 to include a pseudo IP address orFQDN for which a real IP address cannot be determined using only cacheddata stored on the computer system 1300, then the content request may betransmitted 1108 to the intermediary server 118 with the FQDN includedin the request or corresponding to the pseudo IP address included in therequest.

The intermediary server 118 receives 1110 the request with the FQDN andresolves 1110 the FQDN to a real IP address by issuing a DNS requestwith the FQDN and receiving a response or by finding a mapping of theFQDN to the real IP address in locally stored data of the intermediaryserver 118. The intermediary server then adds the real IP address to thecontent request and forwards 1114 the content request to the real IPaddress, i.e. the server assigned the real IP address, which processesthe content request and returns a response to the intermediary server118. The intermediary server 118 receives 1116 the response to thecontent request and returns 1118 the response to the VPR 104 along withthe real IP address for the FQDN as determined at step 1112. Other dateincluded in a response to a DNS request may also be returned, such as aTTL of the real IP address for the FQDN or other real IP addressesassociated with the FQDN or the requested content (see, e.g. FIG. 12 andcorresponding description).

For example, the real IP address or addresses and any additional data(e.g. TTL) may be returned within HTTP headers returned 1118 with therequested content. In another implementation, the real IP address isreturned in a data packet recognized by the VPR 104 from its datapattern or location inside the returned data set. For instance, the realIP address could be returned in a first content packet inserted beforepackets of the requested content. The VPR 104 would retrieve the real IPaddress and remove the first packet before returning the response to therequesting application.

In another implementation, the real IP address for one content requestis returned together with content data for another content request. Inone embodiment, the intermediary server 118, 120 returns a set ofcorrespondences between multiple domain names and their real IPstogether with content data. Domain names corresponding to listed IPscould refer to the previously issued content requests, or to the contentrequests expected to be issued in the future.

For example, after receiving request for the content from the domain A,intermediary server 118, 120 may issue DNS requests for domainsreferenced by the main site A (such domains being already known to theserver, or obtained by parsing HTML response from the domain A) andprovide set of such domains and their real IPs with response for thecontent request from domain A. As a result, the VPR 104 will need to useintermediary server 118, 120 only for the small amount of contentrequests to unknown domains, thereby further improving performance.

The VPR 104 receives the response and stores 1122 the real IP address(or addresses) mapped to the FQDN (or FQDNs), such as by storing thecorrespondence between the FQDN and the real IP address in theFQDN_to_r_IP and r_IP_to_FQDN tables. The response may further bereturned by the VPR 104 to the application that issued the received 1102content request. The response may include or exclude the real IPaddress.

In subsequent iterations of the method 1100 with respect to othercontent requests by the same or different application, the real IPaddress for the FQDN will be found at step 1104 and steps 1108-1122 maybe omitted thereby reducing latency for the subsequent content requestsand bypassing the intermediary server 118, 120.

Referring to FIG. 12, the illustrated method 1200 may be executed by anintermediary server 118 functioning as a proxy server for client devicesthat may or may not be executing a VPR 104 as described herein. Themethod 1200 enables an intermediary server to anticipate at least aportion of subsequent DNS requests and reduce latency by populating acache of a client device with corresponding real IP addresses.

The method 1200 may include receiving 1202 a request for content that isaddressed to a domain name or a real IP address and retrieving 1204 therequested content from the server addressed by the domain name or realIP address, such as by transmitting the content request addressed to thereal IP address and receiving a response to the content request form theserver associated with the real IP address. Where the content requestincludes a domain name, the intermediary server 118 may first resolvethe domain name to a real IP address by retrieving it from a locallystored cache or issuing a DNS request with the domain name and receivinga response with the real IP address.

The method 1200 may further include identifying 1206 related domains forthe content. For example, where the content retrieved 1204 is a webpage, domains reference by links in the web page may be identified 1206.In another example, a list of related domains can be created byobserving previous sets of domain requests following original domainrequests; this method can be used for HTTPS content that can't be parsedby the intermediary server. The method 1200 may further include issuing1208 DNS requests for the related domains and receiving 1210 real IPaddresses for the related domains. The method 1200 may further includereturning the real IP addresses for the related domains and returning1214 the retrieved 1204 content to the client device from which thecontent request was received 1204. Where the content request included adomain, the real IP address for that domain as well as for the relateddomains may be returned 1212. The real IP addresses and content may beincluded in the same or different messages.

Upon receiving the real IP addresses, the client device may cache themsuch that subsequent requests for content may be transmitted directly toservers corresponding to the IP addresses without transmitting of thesubsequent content requests to the intermediary server 118. For example,the client device may store mappings between the related domains and thereal IP addresses in FQDN_to_r_IP and r_IP_to_FQDN tables.

The method 1200 may further include the server preemptively establishingTCP connections to one or more real IP addresses of the related domains,without waiting for the client to send the content requests to thesedomains. After receiving such content request, server passes it to thedestination without waiting for the TCP handshake, thereby improvingperformance.

The method 1200 may further include the server preemptively preformingTLS handshakes for one or more related domains, for instance ones knownto use HTTPS protocol for content requests. To do this, the serverobtains a session ID or a session ticket from the TLS handshakeperformed by the client for a particular domain, uses obtained value topreemptively initiate another TLS handshake for the same domain, andthen passes TLS response to the client. Client caches the TLS responseand returns it to the application after it issues TLS request for thesame domain with the same session ID or a ticket, thereby furtherimproving performance. Server can obtain a session ID or a sessionticket by observing a TLS handshake initiated by the client, or byreceiving such value from the client; neither TLS session ID or asession ticket have to be kept secret because they don't discloseencryption keys that should be known only to the client and the contentprovider.

FIG. 13 is a block diagram illustrating an example computing device 1300which may host a VPR 104. The intermediary server 118, 120 may also havesome or all of the attributes of the computing device 1300. Computingdevice 1300 may be used to perform various procedures, such as thosediscussed herein. Computing device 1300 can function as a server, aclient, or any other computing entity. Computing device can performvarious monitoring functions as discussed herein, and can execute one ormore application programs, such as the application programs describedherein. Computing device 1300 can be any of a wide variety of computingdevices, such as a desktop computer, a notebook computer, a servercomputer, a handheld computer, tablet computer and the like.

Computing device 1300 includes one or more processor(s) 1302, one ormore memory device(s) 1304, one or more interface(s) 1306, one or moremass storage device(s) 1308, one or more Input/Output (I/O) device(s)1310, and a display device 1330 all of which are coupled to a bus 1312.Processor(s) 1302 include one or more processors or controllers thatexecute instructions stored in memory device(s) 1304 and/or mass storagedevice(s) 1308. Processor(s) 1302 may also include various types ofcomputer-readable media, such as cache memory.

Memory device(s) 1304 include various computer-readable media, such asvolatile memory (e.g., random access memory (RAM) 1314) and/ornonvolatile memory (e.g., read-only memory (ROM) 1316). Memory device(s)1304 may also include rewritable ROM, such as Flash memory.

Mass storage device(s) 1308 include various computer readable media,such as magnetic tapes, magnetic disks, optical disks, solid-statememory (e.g., Flash memory), and so forth. As shown in FIG. 13, aparticular mass storage device is a hard disk drive 1324. Various drivesmay also be included in mass storage device(s) 1308 to enable readingfrom and/or writing to the various computer readable media. Mass storagedevice(s) 1308 include removable media 1326 and/or non-removable media.

I/O device(s) 1310 include various devices that allow data and/or otherinformation to be input to or retrieved from computing device 1300.Example I/O device(s) 1310 include cursor control devices, keyboards,keypads, microphones, monitors or other display devices, speakers,printers, network interface cards, modems, lenses, CCDs or other imagecapture devices, and the like.

Display device 1330 includes any type of device capable of displayinginformation to one or more users of computing device 1300. Examples ofdisplay device 1330 include a monitor, display terminal, videoprojection device, and the like.

Interface(s) 1306 include various interfaces that allow computing device1300 to interact with other systems, devices, or computing environments.Example interface(s) 1306 include any number of different networkinterfaces 1320, such as interfaces to local area networks (LANs), widearea networks (WANs), wireless networks, and the Internet. Otherinterface(s) include user interface 1318 and peripheral device interface1322. The interface(s) 1306 may also include one or more user interfaceelements 1318. The interface(s) 1306 may also include one or moreperipheral interfaces such as interfaces for printers, pointing devices(mice, track pad, etc.), keyboards, and the like.

Bus 1312 allows processor(s) 1302, memory device(s) 1304, interface(s)1306, mass storage device(s) 1308, and I/O device(s) 1310 to communicatewith one another, as well as other devices or components coupled to bus1312. Bus 1312 represents one or more of several types of busstructures, such as a system bus, PCI bus, IEEE 1394 bus, USB bus, andso forth.

For purposes of illustration, programs and other executable programcomponents are shown herein as discrete blocks, although it isunderstood that such programs and components may reside at various timesin different storage components of computing device 1300, and areexecuted by processor(s) 1302. Alternatively, the systems and proceduresdescribed herein can be implemented in hardware, or a combination ofhardware, software, and/or firmware. For example, one or moreapplication specific integrated circuits (ASICs) can be programmed tocarry out one or more of the systems and procedures described herein.

What is claimed is:
 1. A method for domain resolution suppression, themethod comprising: intercepting from an application executing on acomputing device by a module executing on the same computing device, adomain resolution request including a domain name, the domain resolutionrequest addressed to a first external server; suppressing, by themodule, transmission of the domain resolution request to the externalserver; returning, by the module to the application, a pseudo internetprotocol (IP) address as a response to the domain resolution request;and storing, by the module, an entry mapping the pseudo IP address tothe domain name of the domain resolution request.
 2. The method of claim1, further comprising: intercepting from the application by the module,a content request including the pseudo IP address; in response tointercepting from the application by the module the content requestincluding the pseudo IP address, generating a modified content requestincluding the domain name mapped to the pseudo IP address in the entry;transmitting the modified content request to one of the first externalserver and a different external server.
 3. The method of claim 2,further comprising performing by the one of the first external serverand the different external server: receiving the modified contentrequest; obtaining a real IP address corresponding to the domain name;requesting content according to the modified content request from thereal IP address; receiving the content according to the modified contentrequest; transmitting the content according to the modified contentrequest to the computing device.
 4. The method of claim 3, whereinreturning, by the module to the application, the pseudo internetprotocol (IP) address as a response to the domain resolution requestcomprises returning the pseudo IP address having a time to live (TTL)attribute set to a value larger than a TTL value used for the real IPaddress.
 5. The method of claim 1, wherein the application is a firstapplication, the domain resolution request is a first domain resolutionrequest, and the domain name is a first domain name, the method furthercomprising: intercepting from one of the first application and a secondapplication executing on the computing device by the module, a seconddomain resolution request including a second domain name; determining,by the module, according to a domain name rule applied to the seconddomain name that the second domain name request should not besuppressed; transmitting, by the computing device, a request to resolvethe second domain name from the computing device to one of the firstexternal server and a second external server; receiving, by thecomputing device, a response to the request to resolve the second domainname; and returning, by the computing device, the response to therequest to resolve the second domain name to the application.
 6. Themethod of claim 1, wherein the application is a first application, thedomain resolution request is a first domain resolution request, thedomain name is a first domain name, and the pseudo IP address is a firstpseudo IP address, the method further comprising: intercepting from oneof the first application and a second application executing on thecomputing device by the module, a second domain resolution requestincluding a second domain name; determining, by the module, according toa domain name rule applied to the second domain name that the seconddomain name request should not be suppressed; in response to determiningaccording to the domain name rule applied to the second domain name thatthe second domain name request should not be suppressed— returning asecond pseudo IP address to the one of the first application and thesecond application; transmitting, by the module, a request to resolvethe second domain name from the computing device to one of the firstexternal server and a second external server; receiving, by the module,a response to the request to resolve the second domain name, theresponse including a real IP address corresponding to the second domainname; and mapping, by the module, the real IP address to the secondpseudo IP address.
 7. The method of claim 1, wherein the application isa first application, the domain resolution request is a first domainresolution request, the domain name is a first domain name, and thepseudo IP address is a first pseudo IP address, the method furthercomprising: intercepting from one of the first application and a secondapplication executing on the computing device by the module, a seconddomain resolution request including a second domain name; returning, bythe module to the application, a second pseudo IP address as a responseto the second domain resolution request; storing, by the module, anentry mapping the second pseudo IP address to the second domain name ina storage location; intercepting from the one of the first applicationand the second application by the module, a content request includingthe second pseudo IP address; obtaining from the storage location thesecond domain name corresponding to the second pseudo IP address;determining, by the module, according to a domain name rule applied tothe second domain name that the second domain name request should not besuppressed; transmitting, by the module, a request to resolve the seconddomain name from the computing device to one of the first externalserver and a second external server; receiving, by the module, aresponse to the request to resolve the second domain name, the responseincluding a real IP address corresponding to the second domain name;generating a modified content request including the real IP address; andtransmitting the modified content request to one of the first externalserver and a different external server.
 8. The method of claim 1,wherein the entry mapping the pseudo IP address to the domain nameincludes a smaller number of bits than a real IP address.
 9. The methodof claim 1, wherein the domain resolution request is a hypertexttransfer protocol (HTTP) request, the method further comprisingextracting the domain name from a HOST header of the HTTP request. 10.The method of claim 1, wherein the domain resolution request istransmission control protocol (TCP) request, the method furthercomprising extracting the domain name from a CONNECT header of the TCPrequest.
 11. A system comprising one or more processing devices and oneor more memory devices operably coupled to the one or more processors,the one or more memory devices storing executable and operational dataeffective to cause the one or more processors to: intercept from anapplication executed by the system by a module executing on the system,a domain resolution request including a domain name, the domainresolution request addressed to a first external server; suppress, bythe module, transmission of the domain resolution request to theexternal server; return, by the module to the application, a pseudointernet protocol (IP) address as a response to the domain resolutionrequest; and store, by the module, an entry mapping the pseudo IPaddress to the domain name of the domain resolution request.
 12. Thesystem of claim 11, wherein the executable and operational data arefurther effective to cause the one or more processors to: intercept fromthe application by the module, a content request including the pseudo IPaddress; in response to intercepting from the application by the modulethe content request including the pseudo IP address, generate a modifiedcontent request including the domain name mapped to the pseudo IPaddress in the entry; transmit the modified content request to one ofthe first external server and a different external server.
 13. Thesystem of claim 12, further comprising one of the first external serverand the different external server, the one of the first external serverand the different external server programmed to: receive the modifiedcontent request; obtain a real IP address corresponding to the domainname; request content according to the modified content request from thereal IP address; receive the content according to the modified contentrequest; transmit the content according to the modified content requestto the computing device.
 14. The system of claim 13, wherein theexecutable and operational data are further effective to cause the oneor more processors to return, by the module to the application, thepseudo internet protocol (IP) address as a response to the domainresolution request comprises returning the pseudo IP address having atime to live (TTL) attribute set to a value larger than a TTL value usedfor the real IP address.
 15. The system of claim 11, wherein theapplication is a first application, the domain resolution request is afirst domain resolution request, and the domain name is a first domainname and wherein the executable and operational data are furthereffective to cause the one or more processors to: intercept from one ofthe first application and a second application executing on the systemby the module, a second domain resolution request including a seconddomain name; determine, by the module, according to a domain name ruleapplied to the second domain name that the second domain name requestshould not be suppressed; transmit a request to resolve the seconddomain name from the system to one of the first external server and asecond external server; receive a response to the request to resolve thesecond domain name; and return the response to the request to resolvethe second domain name to the application.
 16. The system of claim 11,wherein the application is a first application, the domain resolutionrequest is a first domain resolution request, the domain name is a firstdomain name, and the pseudo IP address is a first pseudo IP address andwherein the executable and operational data are further effective tocause the one or more processors to: intercept from one of the firstapplication and a second application executing on the system by themodule, a second domain resolution request including a second domainname; determine, by the module, according to a domain name rule appliedto the second domain name that the second domain name request should notbe suppressed; in response to determining according to the domain namerule applied to the second domain name that the second domain namerequest should not be suppressed— return a second pseudo IP address tothe one of the first application and the second application; transmit,by the module, a request to resolve the second domain name from thesystem to one of the first external server and a second external server;receive, by the module, a response to the request to resolve the seconddomain name, the response including a real IP address corresponding tothe second domain name; and map, by the module, the real IP address tothe second pseudo IP address.
 17. The system of claim 11, wherein theapplication is a first application, the domain resolution request is afirst domain resolution request, the domain name is a first domain name,and the pseudo IP address is a first pseudo IP address and wherein theexecutable and operational data are further effective to cause the oneor more processors to: intercept from one of the first application and asecond application executing on the computing device by the module, asecond domain resolution request including a second domain name; return,by the module to the application, a second pseudo internet protocol (IP)address as a response to the second domain resolution request; store, bythe module, an entry mapping the second pseudo IP address to the seconddomain name; intercept from the one of the first application and thesecond application by the module, a content request including the secondpseudo IP address; obtain from the storage the second domain namecorresponding to the second pseudo IP address; determine, by the module,according to a domain name rule applied to the second domain name thatthe second domain name request should not be suppressed; transmit, bythe module, a request to resolve the second domain name from thecomputing device to one of the first external server and a secondexternal server; receive, by the module, a response to the request toresolve the second domain name, the response including a real IP addresscorresponding to the second domain name; in response to interceptingfrom the one of the first application and the second application by themodule the content request including the second pseudo IP address,generate a modified content request including the real IP address mappedto the second pseudo IP address; and transmit the modified contentrequest to one of the first external server and a different externalserver.
 18. The system of claim 17, wherein the entry mapping the pseudoIP address to the domain name includes smaller number of bits than thereal IP address.
 19. The system of claim 11, wherein the domainresolution request is a hypertext transfer protocol (HTTP) request andwherein the executable and operational data are further effective tocause the one or more processors to extract the domain name from a HOSTheader of the HTTP request.
 20. The system of claim 11, wherein thedomain resolution request is transmission control protocol (TCP)request, and wherein the executable and operational data are furthereffective to cause the one or more processors to extract the domain namefrom a CONNECT header of the TCP request.